Municipal fire hydrants, also known as fire plugs, provide an invaluable and immediate source of water for fire fighters when called upon to respond to fires in either residential, commercial, or industrial structures. In times of emergency, fire hydrants can also provide a secondary source of potable water should the municipal fresh water distribution system become contaminated or inoperable due to a pump station failure. Also, fire hydrants serve as a source of water for municipal sanitation crews when, for example, they are engaged in street cleaning operations.
However, due to the fact that fire hydrants provide a ready and accessible source of clean and fresh water, problems have arisen with theft of water from unmetered fire hydrants. When water is stolen from fire hydrants, not only does the municipality lose the sale of water to an end consumer, such as a residential or commercial user, but the available water supply for use in fighting a fire can be temporarily reduced through reduction in fire water system pressure, or fire water reserves.
Also, municipal fire hydrants are subject to vandalism or theft of parts. In the typical fire hydrant used in the United States, the fire hydrant comprises a generally circular upwardly standing barrel having a mounting flange, to which an arcuate flanged bonnet is bolted. Protruding through the bonnet is an operating nut which can be turned to charge the fire hydrant with water. The operating nut is held within the bonnet by a brass thrust collar. The operating nut is not shielded or enclosed atop the bonnet so that municipal fire departments can gain ready access to the nut in order to turn it for opening an underground water valve to charge the fire hydrant with water. Thus, due to the construction of the fire hydrant and the fact that the operating nut thrust collar is constructed of brass, municipalities have faced problems with individuals improperly removing the brass thrust collars from the fire hydrants with the result that the operating nut does not have the thrust collar to push against, and is thus unable to charge the fire hydrant with water in the event of an emergency. The brass thrust collars are taken to scrap yards or recycling centers, where the brass is sold for its commercial salvage or scrap value.
Attempts have been previously made to prevent the operation of a valve or stop cock, or for locking a cap to an object. For example, U.S. Pat. No. 1,714,856, issued May 28, 1929, to P. S. Douglas discloses a valve locking device which prevents the operation of a valve handle so that the position of the valve gate cannot be altered. In Douglas, this is accomplished through mounting a locking device on the valve body, so that the locking device swings down upon and engages the valve operating wheel with a pair of stops extending downward between spokes of the valve operating wheel. Another early effort to prevent the operation of a valve is disclosed in U.S. Pat. No. 111,943, issued Feb. 21, 1871, to J. Jones, which discloses a bridle and a cap, for locking a stop cock in its seat so that it cannot be tampered with or loosened so as to leak.
U.S. Pat. No. 1,832,057, issued Nov. 17, 1931, to E. G. Stein, and U.S. Pat. No. 973,624, issued Oct. 25, 1910, to M. E. Burley disclose a cap lock, and a locking device for milk can covers, respectively. The patents to Stein, and Burley, however, do not otherwise disclose or teach an apparatus for securing or otherwise shielding an operating nut protruding through a fire hydrant bonnet, or for locking the fire hose outlet(s) of a fire hydrant closed.
None of these known locking devices discloses an apparatus for securing or otherwise enclosing an operating nut of a municipal fire hydrant upon the bonnet of the fire hydrant so that the operating nut cannot be operated, nor can it be tampered with, in order to charge the fire hydrant with water, or to disable the fire hydrant from being charged with water. Nor do any of these known locking devices disclose an apparatus for locking closed the fire hose outlets of a fire hydrant.